We aren’t terribly good at judging how well we’re learning something. Part of that problem results from our tendency to believe that we are learning “better” when we can follow along with ideas more easily. If something seems easy, then of course we’ll remember it. Or so we tend to think.

It turns out that we learn better when we are having a harder time learning something. There are even some very simple things we can do to make learning just a little more difficult, and therefore more effective and long-lasting. What we want are “desirable difficulties,” as Time education writer Annie Murphy Paul says. She explains the importance of making lessons and material just the right difficulty in just the right way:

When we work hard to understand information, we recall it better; the extra effort signals the brain that this knowledge is worth keeping. This phenomenon, known as cognitive disfluency, promotes learning so effectively that psychologists have devised all manner of “desirable difficulties” to introduce into the learning process: for example, sprinkling a passage with punctuation mistakes, deliberately leaving out letters, shrinking font size until it’s tiny or wiggling a document while it’s being copied so that words come out blurry.

That last part is the most interesting to me. Chances are that most teachers pay little attention to the font they use in the materials they create for their classes. Or, if they do, they might just choose the most aesthetically pleasing (my favorite has long been Garamond–a “noble font” as my high school friend used to say). But as teachers, we can actually help induce deeper concentration in our students by choosing a font that is hard to read, but not too hard to read. Using an unfamiliar, hard-to-read font helps the brain remember text far more effectively than do italicized, bold, or large fonts.

In a recent study published in the journal Cognition, psychologists at Princeton and Indiana University had 28 men and women read about three species of aliens, each of which had seven characteristics, like “has blue eyes,” and “eats flower petals and pollen.” Half the participants studied the text in 16-point Arial font, and the other half in 12-point Comic Sans MS or 12-point Bodoni MT, both of which are relatively unfamiliar and harder for the brain to process.

After a short break, the participants took an exam, and those who had studied in the harder-to-read fonts outperformed the others on the test, 85.5 percent to 72.8 percent, on average.

The same is true for studying material multiple times but spreading out your study sessions. You might think that waiting a long time between studying sessions–and the ensuing difficulty you have remembering things the second time around–means that it’s a waste of time. Wrong. Carey’s article again:

“For example, we know that if you study something twice, in spaced sessions, it’s harder to process the material the second time, and people think it’s counterproductive,” said Nate Kornell, a psychologist at Williams College. “But the opposite is true: You learn more, even though it feels harder. Fluency is playing a trick on judgment.”

So try going for some seldom-used fonts on your next worksheet or outline. It might very well help your students in ways they won’t expect. Use Comic Sans or Apple Chancery or Noteworthy. Probably best, however, to avoid all the members of the Wingdings family. Some fonts are just weirder than they are useful.